Improvement in h erm etical seals ng



J. SPRATT.

Fruit Can.

Patented July 18, 1854.

its use.

may be sa'fely'asserted that the publication of IlisrTan STATES PATENT Osman,

JAhIES SPRATT, OF CINCINNATI, OHIO.

IMPROVEMENT lN HERMETICAL SEALlNG.

Specification forming part of Letters Patent No. l H.332, dated July 18, I854.

f0 ail whom it may concern:

Be it known that I JAMES SrRivrr, of Oincinnati, Hamilton county, Ohio, have invented new and useful Improvements in the Her metical Sealing of Preserve-Canisters; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being bad to the annexed drawing, making part of this specification, and in which my device is represented by an axial section through the canister.

Although the established reliability of solder causes it to be employed to the almost entire exclusion of other modes of sealing cans, yet the great tact and nieety needed in handling the soldering-tool and the consequent uncertainty of success in the hands of inexperienced operators very much circumscribes Indeed, so much is this the (3350, 113

a plan that would be easily and safely operated without much previous practice would increase tenfold the amount of provisions put up for domestic use.

In the course of protracted and numerous experiments, made by myself, both with a screw-gasket and with sealing material, I have found the most prompt and at the same time sure method to consist in a combination of both systems, neither of which are, for

practical purposes, of any account alone.

The simple use of wax for aglass jar answers very well, becausefafter the upper portion is cooled, the slow conducting nature of the vessel prevents the remelting of the wax; but such is not the case with metal cans, be cause their rapid conduetion of heat keeps the wax so soft that either the evolution of vapor within causes blow-holes in the wax, or, if this does not occur, the condensation and vacuum within is apt to suck a leak through the still soft wax. These evils are effectually prevented by providing. a means of temporarily closing the passage until the wax has set. Such temporary closing can be effected by the gasket with the aid of the screw 5 but all gaskets which I have employed in connection with mechanical pressure become after a while so modified by evaporation, change of substance, or long compressure as to cease to perfectly fill the seam.

In the course of my experience in putting up provisions I have found that a gum-clastic or such like soft gasket, although entirely efficient as a temporary security, cannot be relied upon as apermanent and hermetical seal, even when considerable pressure is brought to bear upon the joint; and inasmuch as it is. not convenient to apply any sealing -cement until the vessels have considerably cooled there is a liability to a return. of a portion of the expelled air. For these and other reasons that might be cited it is proposed in the present invention. to apply to the canister a a screw-cap, 1), whose inner angle, being lined with a gasket, 0, of gum-elastic, becomes, on the screwing down of the cap or cover b, pinched between the.

under surface thereof and the rim of the raised neck d, which neck is screw-threaded 'on its convex side to fit a concave screw within the cover. Immediately outside of and surrounding the neck is a trough, (5, formed by a small flange, f, projecting upward from the top of the can. The cover being screwed down to its place, the canister maybe safely laid away for a short time until a number of them have been charged, and thus temporarily closed over, and then some suitable sealing materialsuch as a composition of beeswax, tallow, and rosinbeing melted, is poured into these troughs, so as to rise above and effectually close over the joint between the neck and the lower edge of the cover, and the can is then permanently sealed.

This process dispenses entirely with the soldering operation, so difficult to perform, and so liable to imperfection in the hands of an inexperienced operator.

The precise cause of the insufliciency of the simple gasket as a permanent seal for ordinary use I do not profess to determine; but the fact of air generally getting access after some period of exposure is fully verified by experiments during several seasons made by myself and others. This form of scaling is secure and effectual, requires but little tact or experience to. apply, supersedes the soldering process, and is a great saving to the user, because the same cans are available for use again and again.

I do not claim the gasket and screw nor the junction, for the hermetical sealing or closwax-trough separately considered; but ing of preserve-canisters.

I claim as new herein and desire to secure I11 testimony whereof I hereunto set my by Letters Patenthand before two subscribing witnesses.

The screw cap or cover and neck substantially as described, provided with a gasket of JAMES SPRATT' "gum-elastic or like substance at their inner Witnesses: junction, when this is combined with a trough GEO. H. KNIGHT, for containing cement, around their outer I S. F. LAPHAM. 

